Scientific team finds new species of finch living in the Galápagos Islands

 

 

Image: College of Veterinary Medicine & Biomedical Sciences

A team of scientists including Texas A&M University and Uppsala University professor Leif Andersson has discovered the origin of a new species of finch living among Darwin’s finches in the Galápagos archipelago.

Published on Nov. 23 in the journal Science, their study reports that the new lineage was formed by the hybridization of two different species of Darwin’s finches.

Darwin’s finches provide an iconic model for the evolution of biodiversity on earth due to natural selection.

While conducting their field work on the small island of Daphne Major in 1981, Princeton University researchers Rosemary and Peter Grant observed an immigrant male that sang an unusual song and differed in size from all resident species on the island. Throughout their 40 consecutive years of direct observation, the Grants found that a new lineage, which they named the Big Bird lineage, was initiated when that male bred with a resident medium ground finch female.

The couple followed the new putative lineage for six generations, over 30 years. DNA sequence data now have revealed that the immigrant male was a large cactus finch, which, remarkably, must have flown to Daphne from Española island, more than 60 miles to the southeast.

The identification of the Big Bird lineage is significant because while a critical step in speciation is the establishment of reproductive isolation and the process of speciation is usually assumed to take a very long time, in the Big Bird lineage, it happened in just two generations, according to the Grants.

“The interesting aspect of this study is that a hybridization between two distinct species led to the development of a new lineage that after only two generations behaved as any other species of Darwin’s finches,” said Andersson, a professor in the Department of Veterinary Integrative Biosciences and an author on the study. “If a naturalist had come to Daphne Major island without knowing that this lineage arose very recently it would have been recognized as one of the four species on the island. This clearly demonstrates the value of long-running field studies.”

Andersson is a Class of 2013-14 Faculty Fellow with the Hagler Institute of Advanced Study at Texas A&M and recipient of the 2014 Wolf Prize in Agriculture.

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